The wheel hub bearing unit is developed on the basis of standard angular contact ball bearings and tapered roller bearings. It integrates two sets of bearings into one unit and has the advantages of good assembly performance, no clearance adjustment, light weight, compact structure, and large load capacity. Grease can be pre-loaded for sealed bearings, ensuring maintenance-free operation without external wheel hub seals. It is widely utilized in passenger cars and is expanding into truck applications. Its primary function is to reduce friction for the rotating pair and transmit radial and axial loads between the tire/brake disc and the steering knuckle.